Routing traffic off an Interstate 40 span that comes off a landmark Mississippi River bridge should keep that section from sinking further into the ground, an Arkansas highway official said Tuesday.

Arkansas Highway and Transportation Department spokesman Randy Ort said it remains “unknown what, if any, additional work will be needed” on the highway section heading west off the Hernando DeSoto Bridge. Transportation officials closed the entire bridge for nine hours Monday after discovering a support pier of the I-40 span had settled 3 1/2 inches overnight.

“I don’t think this is going to be anything where you’re going to see us take down a pier and put up a new pier,” Ort said.

Ort said westbound traffic was routed onto eastbound lanes — a temporary arrangement that was already scheduled for next week as work continues on an earthquake safety project. The New Madrid fault runs through the area.

Ort said the pier most likely settled as additional pilings were being driven near it in an effort to improve the bridge’s stability. Half of the bridge was open to traffic while crews worked beneath the other side. After the pier settled, drivers would have felt a “barely perceptible” dip, Ort said.

“Just about any structure is going to settle over time,” he said. “When this occurred, even though this was a slight 3 1/2 inches over a 100-foot span, that is still enough concern to move traffic off of it.”

An eight-lane Minneapolis bridge spanning the Mississippi River collapsed Aug. 1, killing 13 people. The bridge was undergoing repairs when it buckled during the evening rush hour.

Officials said the Minneapolis collapse weighed heavily in the decision to close the I-40 bridge Monday.